As a multilayer substrate of this type, a multilayer printed substrate described in Patent Document 1, for example, has been conventionally known. In the multilayer printed substrate described in Patent Document 1, a cavity is disposed between a signal via and a ground pattern. Thereby, a capacitance component of the signal via is suppressed from changing, and therefore an impedance of the signal via is adjusted. As a result, transmission characteristics are prevented from deteriorating due to signal reflection at the signal via.